Question

Given M=32 users A´s private key KRa=5, public Keu KUa (e=173, n=323) and H(x)=x^2mod10^3 (where x=M), prove if 237 is the right signature of M signed by user A

e key KRS public key Ku. (eam, n-123) and H(x):x'modl0 (2590) Given M:32 users A's privat 2. (where x-M). prove if 237 is the right signature of M signed by user A (ie. EH(M)) M' ir

Answer 1

first we calculate the actual signature of message x

h(x) = x ^2 mod 1000

       = 32 ^ 2 mod 1000 = 24

we know that

E(h(m)) = 237

so h(m) = E(h(m)) ^ 173 mod 323 = 237 ^ 173 mod 323 = 271

since h(m) != original signature so this is not the correct signature